Molecular cytogenetic dissection of human chromosomes 3 and 21 evolution.
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Chromosome painting in placental mammalians illustrates that genome evolution is marked by chromosomal synteny conservation and that the association of chromosomes 3 and 21 may be the largest widely conserved syntenic block known for mammals. We studied intrachromosomal rearrangements of the syntenic block 3/21 by using probes derived from chromosomal subregions with a resolution of up to 10-15 Mbp. We demonstrate that the rearrangements visualized by chromosome painting, mostly translocations, are only a fraction of the actual chromosomal changes that have occurred during evolution. The ancestral segment order for both primates and carnivores is still found in some species in both orders. From the ancestral primate/carnivore condition an inversion is needed to derive the pig homolog, and a fission of chromosome 21 and a pericentric inversion is needed to derive the Bornean orangutan condition. Two overlapping inversions in the chromosome 3 homolog then would lead to the chromosome form found in humans and African apes. This reconstruction of the origin of human chromosome 3 contrasts with the generally accepted scenario derived from chromosome banding in which it was proposed that only one pericentric inversion was needed. From the ancestral form for Old World primates (now found in the Bornean orangutan) a pericentric inversion and centromere shift leads to the chromosome ancestral for all Old World monkeys. Intrachromosomal rearrangements, as shown here, make up a set of potentially plentiful and informative markers that can be used for phylogenetic reconstruction and a more refined comparative mapping of the genome. (+info)
Identification of supernumerary marker chromosomes derived from chromosomes 5, 6, 19, and 20 using FISH.
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A large number of cases with supernumerary marker chromosomes (SMCs) should be compared to achieve a better delineation of karyotype-phenotype correlations. Here we present four phenotypically abnormal patients with autosomal marker chromosomes analysed by fluorescence in situ hybridisation using centromeric, telomeric, and unique sequence probes, as well as forward and reverse painting. We also report the first case, to the best of our knowledge, of an SMC derived from chromosome 5. Furthermore, a marker chromosome 20 in a patient with sex differentiation abnormalities, a double mar(6) in a boy with psychomotor retardation, and the association of r(19) with dup(21q21.2q22.12) are described. Although the mar(6) was very small, the presence of euchromatin was shown, suggesting that the partial trisomy of pericentric region derived sequences is implicated in the aetiology of the abnormal phenotypes. (+info)
Chromosomal aberrations evaluated by CGH, FISH and GTG-banding in a case of AIDS-related Burkitt's lymphoma.
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BACKGROUND AND OBJECTIVE: We have previously reported on a complex chromosome rearrangement [der(17)] in a B-cell line, BRG A, established from an AIDS patient with Burkitt's lymphoma (BL). The aim of the present study was the definition of der(17) composition and the identification of complete or partial chromosome gains and losses in two cell clones (BRG A and BRG M) derived from this patient. DESIGN AND METHODS: We applied comparative genome hybridization (CGH) to detect the DNA misrepresentations in the genome of the two cell clones. Findings from CGH and banding analysis could then direct the choice of probes for chromosome painting experiments to elucidate der(17) composition. RESULTS: CGH analysis identified gains of chromosomes 1q, 7q, 12q, 13q, 15q, 17p, 20p,q and losses of chromosomes 3p and 5q in BRG A and gain of chromosome 1q and loss in chromosome 6q in BRG M. Some of the detected alterations had already been described in lymphomas, while others appeared to be new. The combination of these techniques allowed a precise definition of der(17), composed by translocated regions from chromosomes 12 and 15. INTERPRETATION AND CONCLUSIONS: We demonstrated CGH to be a powerful tool in the identification of recurrent chromosome aberrations in an AIDS-related BL and in ascertaining the origin of marker chromosomes. We were also able to identify a different pattern of aberrations and assess an independent sequence of events leading to the 1p gain in the two subclones. (+info)
NOR regions of polychaete worms of the genus Ophryotrocha studied by chromosome banding techniques and FISH.
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This article reports the results of cytogenetic analyses carried out on 10 species of polychaete worms belonging to the genus Ophryotrocha (Dorvilleidae). Nucleolar organizer regions (NORs) were characterized by Ag staining, C-banding, CMA3 staining, and ribosomal fluorescent in situ hybridization (rDNA FISH). Extensive intraspecific variation in NOR number and distribution were observed in O. costlowi, O. sp. macrovifera, O. notoglandulata, O.l. labronica, O. l. pacifica (2n = 6), O. p. puerilis, O. diadema (2n = 8), O. hartmanni, O. gracilis (2n = 10). In O. sp. robusta (2n = 10), Ag-NORs were always located on a single chromosome pair. CMA3 staining suggests a possible trend toward a GC-rich rDNA compartmentalization. In O.l. labronica, O. p. puerilis, O. diadema, and O. sp. robusta rDNA FISH shows that Ag and FISH signals coincide. Results from C-banding seem to indicate that the increased genome size (GS) observed in O. sp. macrovifera (0.8 pg) and O. hartmanni (1.16 pg) compared to the base GS value of the genus (0.4 pg) cannot be attributed to variation in the heterochromatin content. (+info)
A 700-kb physical map of a region of 16q23.2 homozygously deleted in multiple cancers and spanning the common fragile site FRA16D.
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We have identified a >600-kb region at 16q23.2 that is homozygously deleted from malignant ovarian ascites using representational difference analysis. Overlapping homozygous deletions were also observed in the colon carcinoma cell line HCT116 and a xenograft established from the small cell lung cancer cell line WX330. This region coincides with that described previously by others as showing loss of heterozygosity in prostate and breast cancers (C. Li et al., Genes Chromosomes Cancer, 24: 175-182, 1999; A. Latil et al., Cancer Res., 57: 1058-1062, 1997; K. Driouch et al., Genes Chromosomes Cancer, 19: 185-191, 1997; A. Iida et al., Br. J. Cancer, 75: 264-267, 1997). In addition, the minimally deleted region spans the common fragile site FRA16D. We have constructed a 700-kb physical map encompassing the deleted region. By fluorescence in situ hybridization of aphidicolin-induced metaphase chromosomes, we have preliminary data to suggest that P1-derived bacterial artificial chromosome clones from the contig lie on both sides of FRA16D. This is confirmed by extensive fluorescence in situ hybridization analysis of the region reported in the accompanying article (M. Mangelsdorf et al., Cancer Res., 60: 1683-1689, 2000) and is consistent with an involvement of this common fragile site in the loss of 16q23.2 material in various cancer types. The minimally deleted region of approximately 210 kb has been characterized using our own markers and public domain markers. Eleven distinct expressed sequences mapped to the region, providing a basis for identifying the predicted tumor suppressor gene in this region. (+info)
An optimized probe set for the detection of small interchromosomal aberrations by use of 24-color FISH.
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The rapid spread of the use of new 24-color karyotyping techniques has preceded their standardization. This is best documented by the fact that the exact resolution limits have not yet been defined. Indeed, it is shown here that a substantial proportion of interchromosomal aberrations will be missed by all multicolor karyotyping systems currently in use. We demonstrate that both the sensitivity and the specificity of 24-color karyotyping critically depend on the fluorochrome composition of chromosomes involved in an interchromosomal rearrangement. As a solution, we introduce a conceptual change in probe labeling. Seven-fluorochrome sets that overcome many of the current limitations are described, and examples of their applications are shown. The criteria presented here for an optimized probe-set design and for the estimation of resolution limits should have important consequences for pre- and postnatal diagnostics and for research applications. (+info)
Cytogenetic analysis of the tamaraw (Bubalus mindorensis): a comparison of R-banded karyotype and chromosomal distribution of centromeric satellite DNAs, telomeric sequence, and 18S-28S rRNA genes with domestic water buffaloes.
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The karyotype of the tamaraw (Bubalus mindorensis, 2n = 46) was investigated by RBG-banding technique and compared with those of the river and the swamp cytotypes of domestic water buffalo (B. bubalis). The tamaraw karyotype consisted of 6 submetacentric and 16 acrocentric autosome pairs (NAA = 56), and X and Y chromosomes. The RBG-banded karyotype of the three taxa had a high degree of homology, and the tamaraw karyotype could be explained by a Robertsonian translocation between chromosomes 7 and 15 and by a telomere-centromere tandem fusion between chromosomes 4p and 12 of the standardized river buffalo cytotype (2n = 50, NAA = 58). The buffalo satellite I and II DNAs were localized to the centromeric regions of all the tamaraw chromosomes. The biarmed chromosome 2 of the tamaraw resulting from the fusion between chromosomes 7 and 15 of the standard contained much larger amounts of the satellite I DNA than the other biarmed chromosomes, suggesting that this chromosome was formed by a relatively recent Robertsonian fusion. The (TTAGGG)n telomeric sequence was specifically localized to the telomeric region of all the buffalo chromosomes. The 18S + 28S rDNA was localized to the telomeric regions of the chromosomes 5p, 7, 19, 21, and 22 of the tamaraw and of their homologous chromosomes in the river and swamp buffalo cytotypes. (+info)
X trisomy in an infertile bitch: cytogenetic, anatomic, and histologic studies.
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Three copies of the X chromosome were identified in a 5-year-old mixed breed infertile bitch. One year after the cytogenetic examination, the bitch died due to gastritis hemorrhagica, an inflammation of the mucus coat of the stomach. Dental studies showed congenital lack of some premolar and molar teeth. Ovaries were of normal shape and size. Also, histologic sections of the ovaries revealed their normal structure, with two corpora lutea and primary follicles. Phenotypic effects of X trisomy are discussed. (+info)